This application relates to the art of monitoring the temperature and pressure inside a can of carbonated beverage, particularly a can of beer. Specifically, this invention relates to a probe and clamp assembly that is utilized with a battery powered data acquisition system to monitor the pressure and temperature of beer cans, especially during the beer pasteurization process.
This assembly is used to study the effects of process variables, such as CO.sub.2, temperature, fill, and pasteurizer operating conditions on can internal pressure development, information which enables the use of lighter containers by optimizing the operating conditions to reduce internal pressure.
To save metals in aluminum cans and lids, the current trend in can and lid making is to make the walls of the cans and the lids thinner and thinner. As the can walls become thinner, it is more important that can and beverage manufacturers have a way of measuring the pressure within the can to ensure lids and cans will not buckle and reverse during pasteurization or kept in the trunk of a car in the hot summer.
There are commercial devices which are designed for this purpose and there also are a number of devices shown in the patent art for this purpose. However, current devices tend to puncture the top or bottom of the can, and press the ends tightly. This will not allow the ends to grow, caused by high internal pressure developed during pasteurization. The can ends are subjected to unusual stress and may even be deformed. The side walls of present cans are so thin that they are subject to being easily deformed by any unusual stress.
Among the prior art devices known are Cochran U.S. Pat. No. 1,539,937 and Hoff U.S. Pat. No. 1,211,942. These patents show devices which pierce the cap of a bottle and are designed to engage the throat of a bottle while piercing the top wall of the cap. Elert U.S. Pat. No. 4,555,935 is designed to test an empty can to determine if the can meets specifications.
Doudera U.S. Pat. No. 2,737,803 and U.S. Pat. No. 2,749,744 are designed to pierce the top wall of a container. Benjamin U.S. Pat. No. 2,036,618 is a device for piercing the top wall of a container with a probe to measure the temperature thereof. Fredricksen U.S. Pat. No. 1,918,258 shows a combination pressure and temperature measuring device designed to pierce the top of a bottle cap. Neuman U.S. Pat. No. 2,457,707 is designed to sample the gas content of a container by engaging the side wall of the container and piercing the container through the top wall.
Werner U.S. Pat. No. 983,962 involves a U-shaped device with opposed arcuate segments designed to engage portions of a can side wall so that one side can be punctured. The device is designed to pressurize the can so that the soldered seams of the empty can may be tested for tightness. The hole then is designed to be filled with solder so the can may be filled and used.
Bellgardt U.S. Pat. No. 4,569,228 shows a probe which can be inserted into a container for measuring the pressure and temperature of the material in the container. Nelson U.S. Pat. Nos. 4,739,699 and 4,788,871 are designed to measure temperature and pressure in a plastic container.
Other patents known to us include U.S. Pat. Nos. 1,344,515, 2,393,552, 2,512,134, 3,958,448, 4,718,776, 4,733,555 and 4,926,681.
The present invention is placed in a receptacle with a battery operated temperature and pressure sensing device which records temperature and pressure as a function of time. The probe is inserted into the container at the thicker wall of the container so as to reside at the cold spot in the can and the temperature and pressure in the can is recorded through the run. The device monitors process time, pasteurizer zone temperatures, can internal pressure, and calculates pasteurization units (P.U.), CO.sub.2 volume, and beer out temperature at the end of pasteurization. This information is used to determine optium operating conditions for the pasteurizer.
The principal object of the present invention is to provide a device for measuring the temperature and pressure in filled thin wall containers of carbonated beverages. It is another main object of this invention to provide a device for measuring the temperature and pressure in a beverage can which includes a thin band for encircling a circular segment of the side wall of the can to prevent distortion of said wall and at the same time having a hollow needle adapted to penetrate the container wall with internal seal means to prevent loss of container fluid or pressure, and consequent false readings, and secondary seal means to seal the device to the container outer wall.
The sealing system in the clamp allows the probe to be inserted into the container with no liquid or pressure loss. The clamp seals against the sidewall of the can without deforming the container. An internal seal in the clamping device seals against the outside diameter of the probe.
The clamp allows precise positioning of the temperature probe at the coldsport of the container, approximately 0.25 inch above the bottom of the center of the can.
The small mass and volume of the probe minimize the heat effect and provides a fast response to temperature changes in the beer from pasteurizer spray water.
When in use, the clamp is assembled onto the exterior of the can; the probe is inserted into the clamp; the probe penetrates the can and remains in the beer until the monitoring is complete; and then is removed by a technician.
These and other objects and advantages of the present invention will become apparent hereinafter.